Production

Wood yard

The wood yard was rebuilt in 2002 as a state-of-the-art plant. The logs are debarked and the bark is used for energy production. The washed logs are reduced to chips, briefly stored in silos, screened and transported to the digester house.

The Lenzing wood yard is one of the most modern plants of its kind in Europe. This innovative wood processing plant is designed for the production of 230,000 tons of pulp. This is the equivalent of one million tons of wood. The plant processes hard wood (beech). The beech logs are mainly delivered by rail (62%) but also by truck (38%). Quality assessment, weighing and sampling is followed by unloading either directly for production or storage.

The wood processing steps are:

  • Debarking, washing
  • Chipping
  • Intermediate storage (in silos, or in piles for softwood)
  • Screening

Debarking

Logs with a length of up to eight meters are debarked in a drum with a length of 35 meters and a diameter of five meters. Slow rotation (3 to 8 rpm) of the drum rubs the logs aginst each other and results in gentle debarking. The logs are then dropped onto a conveyor belt with a sensor for the detection of oversizes, which stops logs with a diameter in excess of one meter.

Chipping

Having passed the stone trap and the metal detector, the new horizontal chipping unit with ten knife chipper reduces the logs to an optimum chip size of 19 x 30 x 5 millimeters. The resulting fines and the bark are burned on site for energy production.

Intermediate storage:

Part of the bulk good is stored in two silos with a capacity of 10,000 m³ each for supplying pulp production during night and for maintaining a buffer to cover supply down times. A conveyor screw at the bottom of the silo transports the chips out of the silo onto conveyor belts for screening. The acceptable fraction is separated from oversize pieces (re-treated in post-chipping) and from fines. A unique conveyor system, the Ropecon®, transports the accepted fraction to the digester house. Ropecon® is a combination of ropeway and conveyor belt.

The wood yard surface water is collected in a basin and pumped to the waste water treatment system. There are no gaseous emissions.